Running Rough under load and idle

[rasracing]

Here's a good one. Acks like it is missing after warm up. Chugs under a load. installed new plugs wires, cleaned the MAF, IAC, ITC. It runs smooth untill it gets warm. Then acts like it's missing. Lots of confusing info around this topic. Anyone have a good symptom of a bad ECT sensor???????

Temp gauge indicates bottom third of range.

 

[mschacht]

2 things. Check for wet fuel in the vacuum line on the fuel pressure regulator. If wet fuel, replace. Change the solinoid on the IAC. These are 2 common problems.

 

[savagefan]

Listen for vacuum leaks, could be the manifold thing.

 

[MrShorty]

Anyone have a good symptom of a bad ECT sensor???????

ECT is a simple thermistor (resistance is a function of temperature). It's easy enough to put an ohmmeter across the ECT while the engine's at ambient temperature and see if it reads a reasonable resistance. Then warm the engine up and see if it's still reading a reasonable resistance.

The KOEO/KEOR tests include a simple test of the ECT as part of their protocol (They expect to see the ECT read warmer than a certain value). If you perform these tests on a properly warmed up engine and get ECT codes, then that can point you to problems in that circuit. It can be important to remember that codes point to circuits, not sensors. A code can be easily set by a break/short in the wiring between the sensor and the computer.

 

[rasracing]

An Additional note on this one...The transmission wont shift out of first gear untill it warms up. This happened before and ford put a new tranny in about a year ago. Now its doing it again. Took it in and they replaced the govoner. Now it's worse...had to drive three miles in first gear before I was able to manually shift it into second then drive and get it to actually stay in drive. Maybe the modulator is gone. they are going to look at the tranny again tomorrow morning and also having them hook it up to the computer. I'll report the results for future info.

 

[rasracing]

Thanks for the replies...It's awesome to find a place where others know a couple things.

 

[rasracing]

Ford dealer has had it for 4 weeks and can't figure it out. :thumbdwn: They did a diagnostic and said I needed to pay them 106.00 to take the plenum off so they could access injector 5, Swapped it for #3 and gave it back to me. I gave it back to them the next business day with the exact same prob. 1.5 weeks later and they still haven't called. No codes, no bad wires...Hmmmm...

They did take the tranny apart finally. It only had 20,000 miles on it since they put it in 6 months ago. Found metal everywhere. So it looks like they gonna give me a new reman.

They think it may be possible that both issues are connected.

Funny thing is, the loaner they gave me does the same darn thing....

 

[savagefan]

Keep us posted, we all learn here and happy new year.

 

[rasracing]

I was just talking to a friend who was a nissan service mgr, had a friend that was a ford srvc mgr. His 94 rig was running rough, ABS wasn't working right, and his buddy told him to change the rear dif. sensor. He said he did it and all has been well since.

Anyone hear of this one??????????? Or was it just the ABS sensor?